Novolak resins and rubber compositions comprising the same

ABSTRACT

The present invention relates to novolak resins prepared with, inter alia, one or more alkylphenols. The invention further relates to compositions comprising the novolak resins, such as vulcanizable rubber compositions, and to products obtained therewith.

RELATED APPLICATIONS

This application claims priority under 35 U.S.C. § 119(e) to U.S.provisional application No. 60/523,333, filed Nov. 20, 2003, herebyincorporated by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to novolak resins prepared with, interalia, one or more alkylphenols. The invention further relates tocompositions comprising the novolak resins, such as rubber compositions,and to products obtained therewith. Also, the present invention relatesto a process for preparing a rubber composition.

BACKGROUND OF THE INVENTION

Resorcinol and resorcinol-formaldehyde resins have been used in therubber industry in rubber compositions and adhesives. However, one ofthe problems associated with resorcinol and conventionalresorcinol-formaldehyde based resins is the high fuming of these resinsduring rubber compounding. Accordingly, the art has seen severalattempts to address this problem. See, e.g., U.S. Pat. Nos. 5,936,056and 5,945,500. However, the need remains for a resin that has acceptableor no fuming levels yet still satisfactorily offers advantages that areprovided by the conventional (fuming) resins.

Resorcinol resins and/or rubber compositions are mentioned in U.S. Pat.Nos. 4,031,288; 4,167,540; 4,889,891; 5,030,692; 5,206,289; 5,238,991;5,922,797; 5,936,056; 5,945,500; 6,448,318; and 6,472,457. All elevenpatents are hereby incorporated by reference in their entirety byreference.

SUMMARY OF THE INVENTION

The present invention provides novolak resins prepared with, relative tothe total weight of phenolic monomers used in the preparation, 1-40 wt %of phenols having one or more alkyl groups; i.e., alkylphenols.

In one embodiment, the present invention provides novolak resinsprepared by reacting:

-   (a) 1-30 wt % of one or more alkylphenols;-   (b) 1-25 wt % of resorcinol;-   (c) 45-98 wt % of phenol; and-   (d) one or more aldehydes;    wherein said wt % are relative to the total weight of components    (a), (b), and (c).

Also, the present invention provides rubber compositions comprising thepresent novolak resins.

Furthermore, the present invention provides a process for preparing arubber composition. In one embodiment, the process includes:

-   (a) mixing one or more oils and one or more novolak resins to    provide a novolak-oil composition; and-   (b) mixing the novolak-oil composition with one or more rubber    compounds.

Additional aspects, advantages and features of the present invention areset forth in this specification, and in part will become apparent tothose skilled in the art on examination of the following, or may belearned by practice of the invention. The inventions disclosed in thisapplication are not limited to any particular set of or combination ofaspects, advantages and features. It is contemplated that variouscombinations of the stated aspects, advantages and features make up theinventions disclosed in this application.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a chart of Oscillating Disk Rheometry test resultsanalyzing compositions 1, 5, 8, A, C, and D.

FIG. 2 depicts a chart of Original Physical Properties test resultsanalyzing compositions 1, 5, 8, A, C, and D.

FIG. 3 depicts a chart of Heat Aged Physical Properties test resultsanalyzing compositions 1, 5, 8, A, C, and D.

FIG. 4 depicts a chart of Adhesion Properties test results analyzingcompositions 1, 5, 8, A, C, and D.

FIG. 5 depicts a chart of Flex Properties test results test resultsanalyzing compositions 1, 5, 8, A, C, and D.

FIG. 6 depicts a chart of Resilience Properties test results analyzingcompositions 1, 5, 8, A, C, and D.

FIG. 7 depicts a chart of Mooney Viscosity test results analyzingcompositions 1, 5, 8, A, C, and D.

DETAILED DESCRIPTION

The present invention provides novolak resins prepared with, relative tothe total weight of phenolic monomers used in the preparation, 1-40 wt %of alkylphenols, e.g. 1-30 wt %, 1-20 wt %, or 5-20 wt %.

In one embodiment, the present invention provides novolak resinsprepared by reacting:

-   (a) 1-30 wt % of one or more alkylphenols (e.g. 1-25 wt%, 1-20 wt %,    5-20 wt %, or 5-15 wt %);-   (b) 1-25 wt % of resorcinol (e.g. 1-20 wt %, 5-20 wt %, or 5-15 wt    %);-   (c) 45-98 wt % of phenol (e.g. 50-90 wt %, 60-90 wt %, 65-90 wt %,    or 70-85 wt%); and-   (d) one or more aldehydes;    wherein said wt % are relative to the total weight of components    (a), (b), and (c).

Alkylphenols are phenols having one or more alkyl group. Alkylphenolsmay have alkyl groups in the ortho, meta, and/or para positions of thephenol. In one embodiment, the alkylphenols include those having onealkyl group ( “mono-alkylphenols”). In another embodiment, thealkylphenols include those having two alkyl groups (“di-alkylphenols”).

In one embodiment, the alkyl groups of the alkylphenols have at least 4carbon atoms, e.g. at least 8, at least 12, at least 16, at least 20, orat least 24 carbon atoms. Generally, the alkyl groups will comprise lessthan 60 carbon atoms, e.g. less than 40, less than 35, less than 30, or28 or less carbon atoms.

Examples of the one or more aldehydes include formaldehyde,methylformcel, butylformcel, acetaldehyde, propionaldehde,butyraldehyde, crotonaldehyde, benzaldehyde, and furfural. In oneembodiment, the one or more aldehydes include formaldehyde.

The present novolak resins may be prepared in any suitable manner. Forinstance, in one embodiment, non-resorcinol phenols are reacted firstwith one or more aldehydes in the presence of a catalyst (e.g. an acidcatalyst, for instance a sulfonic acid catalyst such as p-toluenesulfonic acid or dodecylbenzensulfonic acid) to form a first resin.Resorcinol and optionally additional non-resorcinol phenols may then beadded to the first resin, followed by the addition of additionalaldehyde.

In one embodiment, the present novolak resins comprise less than 5 wt %free resorcinol, e.g. less than 3 wt %, less than 1 wt %, less than 0.5wt %, or about 0 wt %.

In one embodiment, the present novolak resins are used in rubbercompositions, i.e. compositions comprising one or more rubber compounds.Preferably, the rubber compositions are vulcanizable rubbercompositions.

Examples of rubber compounds include both synthetic and natural rubbers.Representative synthetic rubbery polymers include the butadienepolymers. Butadiene polymers include those polymers having rubber-likeproperties which are prepared by polymerizing butadiene alone or withone or more other polymerizable ethylenically unsaturated compounds,such as styrene, methylstyrene, methyl isopropenyl ketone andacrylonitrile. Further examples of synthetic rubbers include neoprenerubbers. Isobutylene rubber (butyl) and ethylenepropylene rubber (EPDM)may also be employed.

In one embodiment, the weight ratio of the one or more rubber compoundsto the novolak resin is in the range of 99:1 to 90:10, e.g. in the rangeof 99:1 to 95:5.

Also, the rubber composition may comprise a methylene donor. Suitablemethylene donors include, for instance, hexamethylenetetramine (HMTA),di-, tri-, tetra-, penta-, or hexa-N-methylol-melamine or theirpartially or completely etherified or esterified derivatives, forexample hexamethoxymethylmelamine (HMMM), oxazolidine orN-methyl-1,3,5-dioxazine.

The rubber composition of this invention may also include one or moreadditives, for instance additives selected from the group consisting ofsulfur, carbon black, zinc oxide, silica, anti-oxidant, stearates,accelerators, a cobalt, and adhesion promoters. In one embodiment therubber composition is absent cobalt.

In one embodiment, the rubber composition further comprises areinforcing material. Examples of reinforcing materials include nylon,rayon, polyester, aramid, glass, steel (brass, zinc or bronze plated) orother organic and inorganic compositions. These reinforcing materialsmay be in the form of, for instance, filaments, fibers, cords orfabrics.

In one embodiment, the rubber composition comprises one or more oils.Suitable oils, include for instance mineral oils and naturally derivedoils. Examples of naturally derived oils include, for instance, talloil, linseed oil, and/or tung oil. Commercial examples of tall oilinclude, e.g., SYLFAT FA1 from Arizona Chemicals and PAMAK C40S fromHercules Canada. In one embodiment, the rubber composition comprises,relative to the total weight of rubber compounds in the composition,less than 5 wt % of one or more oils, such as less than 2 wt %, lessthan 1 wt %, less than 0.6 wt %, less than 0.4 wt %, less than 0.3 wt %,or less than 0.2 wt %. In one embodiment, the rubber compositioncomprises, relative to the total weight of rubber compounds in thecomposition, at least 0.01 wt % of one or more oils, e.g. at least 0.05wt % or at least 0.1 wt %. The presence of an oil in the rubbercomposition may aid in providing improved flexibility of the rubbercomposition after vulcanization.

One aspect of the invention relates to a process for forming the rubbercomposition. In one embodiment, the process of forming the rubbercomposition comprises mixing one or more novolak resins (e.g., the abovedescribed novolak resins) with one or more oils (e.g., the abovedescribed oils, such as the above-described naturally derived oils) toform a novolak resin-oil mixture, and mixing the novolak resin-oilmixture with one or more rubber compounds (e.g., one or more of theabove-described rubber compounds). Pre-mixing the novolak resin and oilbefore combining them with the rubber compounds may result in betterflexibility of the rubber composition after vulcanization and/or in areduction of oil that needs to be used.

In one embodiment, the novolak resin-oil composition comprises, relativeto the total weight of the composition, 0.5-20 wt % of one or more oils,e.g. 1-15 wt % or 2-10 wt %.

In one embodiment, the weight ratio of the one or more rubber compoundsin the rubber composition to the novolak-oil composition is 99:1 to80:20, e.g. 98:2 to 90:10.

The present rubber compositions are useful to make (parts of) a widevariety of products, including, e.g., tires, hoses, power belts,conveyor belts, printing rolls, rubber shoe heels, rubber shoe soles,rubber wringers, automobile floor mats, mud flaps for trucks, ball millliners, and weather strips. In one embodiment, the compositions are usedto make wire belt skim coats.

In a preferred embodiment, the invention relates to a tire comprising anovolak resin that contains phenolic monomers, wherein 1-40 wt % of thephenolic monomers in the resin are alkylphenols. The novolak resin maycontain (a) 1-30 wt % alkylphenols; (b) 1-25 wt % resorcinol; (c) 45-98wt % phenol; and (d) one or more aldehydes; wherein the weightpercentages are based on the total weight of components (a), (b), and(c). The alkyl groups in the alkylphenols may be one or more C₄-C₆₀alkyl groups or one or more C₂₄-C₂₈ alkyl groups.

EXAMPLES

The following examples are given as particular embodiments of theinvention and to demonstrate the practice and advantages thereof. It isto be understood that the examples are given by way of illustration andare not intended to limit the specification or the claims that follow inany manner.

Glossary

Abbreviation Ingredient (Supplier) Rubber natural rubber “SIR 10”(Astlett Rubber). N-326 carbon black (Degussa). TMQ trimethylquinonepara phenylene antioxidant (Uniroyal). 6DDP diamine antioxidant(Vanderbilt). Cobalt manobond680Cobalt (OM Group). Crystex Sulfur sulfurvulcanizing agent (Flexsys). DCBS dicyclobenothiazole sulfonamide(Flexsys). HMMM hexamethylmethoxyamine “Cyrez 963” (Cytec). Tall oil“Sylfat FA1” (Arizona Chemicals).Resin 1

355 g of a mixture of alkylphenols having alkyl groups in the range ofabout 24-28 carbon atoms (LCAP24-28 from Schenectady International), 974g of phenol, and 14 g dodecylbenzene sulfonic acid (catalyst) wereloaded in a flask and mixed while heating the flask to 90° C. 410 g offormaldehyde (50% aqueous solution) was then slowly added to the flaskwhile keeping the temperature in the in the range of 90-100° C. Aftercompletion of the ensuing reaction, 355 g resorcinol and 1862 g phenolwere added to the flask (90° C.). 520 g formaldehyde was then addedslowly while maintaining the flask at 90° C. After completion of theensuing reaction, 1,8 diazabicyclo (5,4,0) undecene-7 (“DBU”) was addedto neutralize the mixture in the flask. The water and unreacted phenolin the mixture were distilled off first at 170° C. and atmosphericpressure and then at 180° C. at 74 torr.

In the monomer feedstock, the weight percentages of the phenolicmonomers in the monomer feedstock are approximately 10% LCAP24-28, 10%resorcinol, and 80% phenol, based on the total weight of the phenolicmonomers. For the final product, the weight percentages of the phenolicmonomers are approximately 20% LCAP24-28, 20% resorcinol, and 60%phenol, based on the total weight of the phenolic monomers.

Resin 2

600 g of para-t-butyl phenol (“pTBP”), 729 g of phenol, and 12 gdodecylbenzene sulfonic acid (catalyst) were loaded in a flask and mixedwhile heating the flask to 90° C. 441 g of formaldehyde (50% aqueoussolution) was then slowly added to the flask while keeping thetemperature in the in the range of 90-100° C. After completion of theensuing reaction, 300 g resorcinol and 1380 g phenol were added to theflask (90° C.). 560 g formaldehyde was then added slowly whilemaintaining the flask at 90° C. After completion of the ensuingreaction, 6 g DBU was added to neutralize the mixture in the flask. Thewater and unreacted phenol in the mixture were distilled off first at170° C. and atmospheric pressure and then at 180° C. at 74 torr.

The novolak resin obtained by this procedure was then melt-blended with65 g Tall oil at a temperature in the range of 140° C.-160° C.

Resin 3

526 g of para-dodecyl phenol (“pDDP”), 1125 g of phenol, and 4 gdodecylbenzene sulfonic acid (catalyst) were loaded in a flask and mixedwhile heating the flask to 90° C. 450 g of formaldehyde (50% aqueoussolution) was then slowly added to the flask while keeping thetemperature in the in the range of 90-100° C. After completion of theensuing reaction, 373 g resorcinol and 1687 g phenol were added to theflask (90° C.). 795 g formaldehyde was then added slowly whilemaintaining the flask at 90° C. After completion of the ensuingreaction, 2 g DBU was added to neutralize the mixture in the flask. Thewater and unreacted phenol in the mixture were distilled off first at170° C. and atmospheric pressure and then at 180° C. at 74 torr.

The novolak resin obtained by this procedure was then melt-blended with50 g Tall oil at a temperature in the range of 140° C.-160° C.

Resin 4

The preparation of Resin 3 was repeated except that 373 g pDDP was usedinstead of 526 g pDDP.

Resin 5

The preparation of Resin 1 was repeated. The thus obtained novolak resinwas then melt-blended with 125 g Tall oil at a temperature in the rangeof 140° C.-160° C.

Resin 6

The preparation of Resin 3 was repeated except that 750 g pDDP was usedinstead of 526 g pDDP.

Resin 7

The preparation of Resin 1 was repeated. The thus obtained novolak resinwas then melt-blended with 65 g Tall oil at a temperature in the rangeof 140° C.-160° C.

Resin 8

The preparation of Resin 1 was repeated except that the amount ofresorcinol and LCAP24-28 monomers were altered so that the weightpercentage of the phenolic monomers in the monomer feedstock are 15%LCAP24-28, 5% resorcinol, and 80% phenol, based on the total weight ofthe phenolic monomers.

Resin A

Resin A is a commercial resorcinol-formaldehyde resin containing about20-25% free resorcinol (“B18S” from Indspec). The resin is produced byreacting formaldehyde with resorcinol and distilling off the water.

Resin B

Resin B is a commercial phenol/formaldehyde novolak resin with cashewnut oil reacted onto the backbone (“HRJ-1 1995” from SchenectadyInternational).

Resin C

Resin C is a commercial resorcinol-formaldehyde resin similar to ResinA, but containing between 10-16% free resorcinol (“B19S” from Indspec).

Resin D

Resin D is a commercial resorcinol-formaldehyde resin containing lowamounts of free resorcinol (“B20S” from Indspec). When making Resin D,styrene is reacted into the resin to scavenge free monomers.

Rubber compositions were prepared for each of Resins 3-8 and A-D bycompounding the following components:

Amount Ingredient (pbw) One of Resins 3-8, A-D 3 Rubber 100 N-326 55Zinc Oxide 8 Stearic Acid 1 TMQ 1 6DDP 2 Cobalt 0.5 Crystex Sulfur 5DCBS 0.8 HMMM 3

The rubber compositions in the following tables are numbered inaccordance with the Resin they comprise (e.g., “Comp. 3” or “Composition3” refers to the rubber composition comprising Resin 3).

The first set of data tests Compositions 3-7 against ComparativeCompositions A and B (see infra for test methods), with the results setforth in the following Table.

Comp. 3 Comp. 4 Comp. 5 Comp. 6 Comp. 7 Comp. A Comp. B Mooney Viscosityinitial 95.4 88.3 88.5 91.4 83.4 85.5 89.8 at 4 min. 75.1 67.4 67.8 75.467.5 69.4 69.1 ODR Cure t1 2.4 2.8 2.9 2.5 2.8 2.8 2.8 t90 7.7 8.7 8.87.8 8.8 8.3 8.8 Wire Adhesion Peak load original 154 156 143 158 150 154148 Peak load aged 165 150 152 165 154 155 143 humidity aged (21 days)154 137 140 154 129 132 144 salt bath aged (96 hrs) 130 128 111 127 104118 118 Hardness Shore A Room Temp. 85 80 78 87 80 77 80 Shore A 100° C.89 84 82 91 83 80 83 Rubber to Rubber 61 127 170 56 208 138 158 AdhesionTest Methods:Mooney Viscosity

The Mooney viscosity was determined in accordance with ASTM D 1646-00,which method is hereby incorporated in its entirety by reference.

ODR Cure

ODR cure data was determined in accordance with ASTM 2085-01, whichmethod is hereby incorporated in its entirety by reference. t1=“time tocure for 1%” of the cure (minutes). t90 is “time to cure for 90%” of thecure (minutes).

Wire Adhesion

Wire adhesion data was determined in accordance with ASTM D2229-99,which method is hereby incorporated in its entirety by reference.

Hardness

Hardness data was determined in accordance with ASTM D412-98a &D2240-02, which methods are hereby incorporated in their entirety byreference.

Rubber to Rubber Adhesion

Rubber to rubber adhesion data was determined in accordance with ASTMD413-98, which method is hereby incorporated in its entirety byreference.

Next, Resins 1, 5, and 8 (as Compositions 1, 5, and 8) were testedagainst Resins A, C, and D (as Compositions A, C, and D) in thefollowing tests: cure rate, hardness, tensile strength, elongation,elasticity, adhesion, flexibility, resistance, and viscosity. A “blank”composition, which contains all the components of the composition exceptfor the resin, was also included with each of these tests. As known bythose of skill in the art, a composition without a resin component willdeteriorate at high temperatures, and is therefore unacceptable for usein products under high-temperature conditions, such as commercial-gradetires. The blank was used in these examples as a reference.

The following tests were performed by Akron Rubber DevelopmentLaboratory, Inc. of 2887 Gilchrist Road, Akron, Ohio.

The first test parameter is ODR (Oscillating Disk Rheometry). This is acure rate test with two different rates, cure and scorch. Cure is thetotal cure time to a specified cure state, and scorch is a measure ofthrough cure, which relates to the cure rate between the center of thecomposition and the outside of the composition. The cure rates aretested in accordance with ASTM D 2084-01 using a Tech Pro rheoTECH ODRat 148.9° C. (300° F.), 3° arc, 100 inch lbs (torque range), 60 minutechart, and 1.7 Hz.

The chart depicted in FIG. 1 shows that Compositions 1, 5, and 8 allhave faster cures than Comparative Composition D. As the differencebetween 23 and 25 minutes is not that significant in the filed of tiremanufacturing, Compositions 1, 5, and 8 all have acceptable cure rates.All the compositions also have acceptable scorch numbers.

In the original physical properties chart depicted in FIG. 2, the shoreA durometer, tensile strength, ultimate elongation, 100% modulus, and300% modulus were measured for the seven compositions. The propertieswere tested on a cured piece of rubber to characterize the strength ofthe cure. The physical properties are measured in accordance with ASTM D412-98a(02) and D 2240-02b, with the Die C dumbbells tested at 20in/min. The measurements for Composition A are normalized to 100%, andthe values for the other compositions are adjusted accordingly. Thechart depicted in FIG. 2 shows that Compositions 1, 5, and 8 generallyperform better (higher tensile strength, better elongation, and betterstress) than Comparative Compositions A, C, and D.

The heat aged test measures shore A durometer, tensile strength, andelongation under heat aged conditions. This test was measured inaccordance with ASTM D 573-99, with specimens aged 72 hours at 158° F.in a forced air oven. The measurements for Composition A are normalizedto 100%, and the values for the other compositions are adjustedaccordingly. As seen from the chart depicted in FIG. 3, Compositions 1,5, and 8 performed better than Comparative Compositions A, C, and D.

Adhesion is an indicator of how well the resin in the composition willassist the rubber in binding to steel belts in a tire. Adhesion may bemeasured as adhesion to a flexible substrate or as wire adhesion, eitherat room temperature (76° F.) (wire adhesion original) or 21 days at 176°F., 98% RH (wire adhesion aged). Adhesion to a flexible substrate ismeasured in accordance with ASTM D 413-98(02), with 0.25-inch widespecimens tested at 2 in/min. The average of the peaks was reported.Both wire adhesion tests were measured in accordance with ASTM D2229-02, with specimens tested at 2 in/min and pulled from a 0.5-inchblock of rubber. The average of 15 specimens was reported. For all threetests, the measurements for Composition A are normalized to 100%, andthe values for the other compositions are adjusted accordingly.

The graph depicted in FIG. 4 shows that the flexible adhesion ofComposition 5 is far superior to Comparative Compositions A, C, and D.The wire adhesions of Compositions 1, 5, and 8 are on par or better thanthose of Comparative Compositions A, C, and D.

Demattia flexibility is an indication of rubber stiffness/flexibility inthe cure. The Demattia flexibility test attempts to imitate the impact atire receives upon hitting a bump in the road. The tests were measuredin accordance with ASTM D 813-95(00), with pierced specimens tested at300 cpm. As shown in the chart depicted in FIG. 5, Compositions 1 and 8performed equal to Comparative Compositions A, C, and D, whileComposition 5 outperformed Comparative Compositions A, C, and D.

Resilience to rebound measures a composition's ability to absorb energyand release the energy as heat. The higher a resilience percentage, thebetter a composition is able to absorb and release the energy. Bashoreresilience is measured at room temperature (76° F.) and room temperatureimmediately after 30 minutes conditioning at 212° F. (100° C.). Bothtests are run in accordance with ASTM D 2632-88, with a 16-inch dropheight. The measurements for Composition A are normalized to 100%, andthe values for the other compositions are adjusted accordingly. Thechart depicted in FIG. 6 shows that Composition 5 has a betterresilience to rebound than Comparative Composition D, while Compositions1 and 8 are on par with Comparative Composition D.

Mooney viscosity attempts to measure the ability of a rubber compositionto be processed by, for example, a manufacturer. The lower the viscosityof the composition, the easier that compositions is to process. Mooneyviscosity is measured in accordance with ASTM D 1646-00 with an AlphaTechnologies Mv2000 viscometer, with CML 1+4 at 100° C. (212° F.).Measurements were taken initially and at four minutes. The measurementsfor Composition A are normalized to 100%, and the values for the othercompositions are adjusted accordingly. The graph depicted in FIG. 7shows that Compositions 1, 5, and 8 are very similar in processingviscosity as compared to Comparative Compositions A, C, and D.

In conclusion, the cumulative data confirm that Compositions 1, 5, and 8(made from Resins 1, 5, and 8) are viable alternatives for the currentcommercial embodiments shown in Compositions A, C, and D (made fromResins A, C, and D), performing as well or better in the testsassociated with evaluating the performance of resorcinol and resorcinolresins.

Having described specific embodiments of the present invention, it willbe understood that many modifications thereof will readily be apparentto those skilled in the art, and it is intended therefore that thisinvention is limited only by the spirit and scope of the followingclaims.

1. A novolak resin, wherein the resin comprises: (a) 1-30 wt %alkylphenols; (b) 5-20 wt % resorcinol; (c) 45-98 wt % phenol; and (d)one or more aldehydes; wherein the weight percentages are based on thetotal weight of components (a), (b), and (c).
 2. The novolak resin ofclaim 1, wherein one or more of the alkyl groups in the alkylphenols isa C₄-C₆₀ alkyl group.
 3. The novolak resin of claim 2, wherein one ormore of the alkyl groups in the alkylphenols is a C₂₄-C₂₈ alkyl group.4. The novolak resin according to claim 1, wherein one or more of thealdehydes is formaldehyde.
 5. The novolak resin according to claim 1,wherein the resin comprises: (a) 5-20 wt % alkylphenols; (b) 5-15 wt %of resorcinol; (c) 65-90 wt % of phenol; and (d) one or more aldehydes;wherein the weight percentages are based on the total weight ofcomponents (a), (b), and (c).
 6. The novolak resin according to claim 5,wherein the resin comprises: (a) 5-15 wt % alkylphenols; (b) 5-15 wt %resorcinol; (c) 70-90 wt % phenol; and (d) formaldehyde; wherein theweight percentages are based on the total weight of components (a), (b),and (c).
 7. A composition comprising one or more rubber compounds andthe novolak resin according to claim
 1. 8. The composition of claim 7,wherein the weight ratio of said one or more rubber compounds to saidnovolak resin ranges from about 99:1 to about 9:1.
 9. A product preparedat least in part by vulcanizing the composition according to claim 7.10. The product of claim 9, wherein said product is selected from thegroup consisting of tires, hoses, power belts, conveyor belts, printingrolls, rubber shoe heels, rubber shoe soles, rubber wringers, automobilefloor mats, mud flaps for trucks, ball mill liners, and weather strips.11. The product of claim 9, wherein said product is a wire belt skimcoat.
 12. A tire comprising a novolak resin, wherein the novolak resincomprises: (a) 1-30 wt % alkylphenols; (b) 5-20 wt % resorcinol; (c)45-98 wt % phenol; and (d) one or more aldehydes; wherein the weightpercentages are based on the total weight of components (a), (b), and(c).
 13. The tire of claim 12, wherein one or more of the alkyl groupsin the alkylphenols is a C₄-C₆₀ alkyl group.
 14. The tire of claim 12,wherein one or more of the alkyl groups in the alkylphenol is a C₂₄-C₂₈alkyl group.
 15. A process for preparing a rubber composition,comprising the steps of: (a) mixing one or more oils with one or morenovolak resins of claim 1 to produce a novolak-oil composition; and (b)mixing said novolak-oil composition with one or more rubber compounds toproduce a rubber composition.
 16. The process according to claim 15,wherein mixing said one or more oils with said one or more novolakresins is effected by melt blending.
 17. The process according to claim15, wherein one or more of the oils is a naturally derived oil.
 18. Theprocess according to claim 15, wherein one or more of the oils is a talloil, a linseed oil, or a tung oil.
 19. The process according to claim15, wherein the weight percentage of said one or more oils ranges fromabout 0.5 to about 20 wt %, based on the total weight of saidnovolak-oil composition.
 20. The process according to claim 19, whereinthe weight percentage of said one or more oils ranges from about 2 toabout 10 wt %.
 21. The process according to claim 15, wherein one ormore of the alkyl groups in the alkylphenols is a C₈-C₆₀ alkyl group.22. The process according to claim 15, wherein the weight ratio of saidone or more rubber compounds to said novolak-oil composition ranges fromabout 99:1 to about 4:1.
 23. The process according to claim 22, whereinsaid ratio ranges from about 49:1 to about 9:1.
 24. The processaccording to claim 15, wherein one or more of the alkyl groups in thealkylphenols in the novolak resins is a C₄-C₆₀ alkyl group.
 25. Theprocess according to claim 15, wherein one or more of the alkyl groupsin the alkylphenols in the novolak resins is a C₂₄-C₂₈ alkyl group.